The disclosure relates to an arrangement of two substrates, which are connected to one another by means of an SLID (solid-liquid interdiffusion) bond, and to a method for producing such an arrangement.
In order to connect two substrates to one another, it is known firstly to provide these with bonding materials and then to carry out a bonding process. One possible bonding process consists in the use of the so-called SLID technology. The SLID technology is based on the selection of two suitable metals with melting points of different magnitudes as the bonding materials, where the two metals together form a stable alloy having a melting point which is higher than the lower melting point of the two starting metals. During the bonding process, the two bonding materials are moved into contact and heated to above the melting temperature of the lower melting point, such that the metal with the lower melting point melts and diffuses into the higher-melting metal. In this case, the desired, solid alloy forms on the boundary layer. The lower-melting metal ideally melts entirely and is converted completely into the newly formed alloy.
The use of such an SLID bond between two substrates is described, for example, in DE 10 2006 019 080 B3. This document proposes the use of tin (Sn) as the first metal with the lower melting temperature and copper (Cu) as the second metal with the higher melting temperature. Upon heating to above the melting temperature of tin, tin diffuses into the copper and thereby forms an alloy having a melting point which is higher than that of tin. According to this document, a solid metallic bond has formed after a duration of several minutes.
However, the Cu/Sn material selection known from the prior art is not always possible or is possible only with major additional expenditure. For example, it is often the case that many known semiconductor processes are already optimized for specific metallic materials, and therefore a simple adoption of the SLID technology known from the prior art in existing semiconductor processes cannot be realized.
There is therefore a need to provide a modified SLID technology which can also be easily introduced into existing semiconductor processes in which the material selection known to date requires major expenditure for adaptation.